Transcript Slide 1

Schematic Design of an
Accelerated Bridge
Construction Project
Michael P. Culmo, P.E.
Vice President of Transportation and Structures
CME Associates, Inc., East Hartford, CT
Reference Manual
• Use the Connections Details
Manual
– Type study concept
– Select details from various
states
Case Scenario
• 4 lane bridge over an expressway
• Existing bridge has deteriorated beyond
repair
• Heavy traffic on both roadways
• There is a short but undesirable detour
Public Involvement
• Public hearing held
• Businesses do not want a long
construction process with stage
construction
• Businesses are not keen about a detour
• They will accept a short term closure with
the detour
– As opposed to a long term staged project
Design Approach Options
• Build a temporary bridge to speed up
construction of the new bridge
– $$$$
– Not that fast
• Use multi-stage construction
– Very long construction
– Will require long term lane closures
• Establish the detour and accelerate the bridge
construction to less than 30 days
Existing Bridge
Existing bridge issues
Deck Joints
Low Clearance
Proposed Bridge Type
• After a formal type study, the owner opted with
the following structure criteria
– Use NEXT Beams to accelerate construction
• Design as simple span for Dead Load and continuous spans
for Live Load
–
–
–
–
Increase clearance by raising approach grades (3’)
Use integral abutments (no deck joints)
Composite concrete deck
Membrane waterproofing and Bituminous wearing
surface
– Use Precast Rail System
• (Vermont/NH system)
Substructures
• Push abutments back to top of slope
– Minimize wingwall requirements
– Use integral abutments with flying wings
– Eliminate spray attack on abutments
• Place abutments in a different footprint than the
existing
– facilitates construction
• Use open frame pier bent on spread footings
Proposed Bridge
Move abutment away from
roadway
No Deck joints
Increase vertical clearance
Bridge Section
Beam Design
• Preliminary
Beam Sizing
– Use PCI NEXT
Beam Standards
Beam Design
• LLDF
Beam Design
• AASHTO LL Distribution Factor – Type K
Moment
Shear
Beam Design
• AASHTO LLDF
Type H
Shear
Moment
Beam Design
Structure Type
H
K
LLDF
Moment
0.96
0.752
LLDF
Shear
1.17
0.938
How to select details
FHWA manual “Connection details for
prefabricated bridge elements and
systems”
1. Review Chapter 1
•
Investigate connection types, materials,
tolerances
2. Search applicable sections of other chapters
for details
Section 1.4 Typical Connection Types
• After reviewing chapter 1, the owner chose the
following connection types
– Grouted reinforcing splice couplers
• Quick, proven system
• Can develop full bar strength
• Simplifies the design process (similar to CIP)
– Grouted Voids
• Easy for simple connections
– Concrete Closure pours between precast elements
• Use for a limited number of connections (slower)
Grouted Reinforcing Splice Connectors
• Emulates a reinforcing
steel lap splice
• Multiple companies –
non-proprietary
• Used in precast parking
garages and stadiums
and bridges
Grouted Reinforcing Splice Connectors
• Emulates a reinforcing
steel lap splice
• Multiple companies – nonproprietary
• Used in precast parking
garages and stadiums and
bridges
• Time Lapse Video on
YoutubeTM
– Search “Georgia Pier
Construction”
• Installation Video on YoutubeTM
Search “Georgia Pier Construction”
Installation video
Footing to Sub-grade Connection
Footing Details
Footing to Column Connection
Footing to Column Connection
Column to Cap Connection
Column to Cap Connection
Completed Pier
Column to cap
connection
Column to footing
connection
Footing to subgrade
connection
Abutment Details
• Integral Abutment to precast piles
– Section 3.2.3.1 Precast Integral Abutment to
Piles
• Detail developed by Maine DOT
– Used on three different bridges
Abutment to Pile Connection
Abutment to Pile Connection
Abutment To Wingwall Connection
Abutment To Wingwall Connection
Approach Slab Connection
Completed
Abutment
Approach slab connection
Flying Wingwall
connection
Abutment cap connection
Pile to cap connection
Deck Design with Next Beam
• Design as a conventional cast in place deck
– Use max stem spacing for design (5.0 feet)
– Design overhang from outside stem (2.53 feet)
Parapet Connection
Parapet Connection
Superstructure to Integral Abutment Connection
Use a similar
detail at the
pier
Composite Deck
Membrane waterproofing
with bit. Wearing surface
Precast Parapet
Completed
Bridge
Precast Pier
Precast Integral
Abutment
Final Bridge
Estimated Construction Schedule
Costs
• Typical New Bridge (Cost=$200/sf) =
$1,920,000
• Premium for ABC (assume 20%) =
$384,000
• Temporary Bridge (Cost=$60/sf) =
($576,000)
Net Savings =
Note: These prices will vary by region
$192,000
Other Cost Savings
• Ways to reduce bid prices with ABC
•
•
•
•
•
Standardization
Programmatic (not one of a kind)
Reduced project site costs (trailers, etc.)
Reduced Maintenance of Traffic Costs
Inflation
• Other Non- Bid Savings with ABC
• Fewer Police Details
• Reduced Resident Engineering time
• User Costs
• Plus: $$ Can be significant
• Minus: $$ Not in the budget
Quality
• Florida has had very good success with
precast piers in very harsh environments
• Precast concrete beams require no
maintenance
• Integral abutments eliminate deck joints
Old Adage
You can only
have any two
High Quality
Rapid
Construction
Low Cost
By elimination of temporary bridges or costly
stage construction schemes,
you CAN have all three
Conclusions
• It is possible to build a complete bridge in 30
days (or less)
• The FHWA manual provides a starting point for
a complete bridge prefabrication project
• You do not need to sacrifice quality to get rapid
construction
• You can save money on an accelerated bridge
project by:
– Reducing construction time
– Eliminate temporary bridges or staging
Questions
[email protected]